1. Field of the Invention
This invention relates to a safety alarm cooperating with existing controls for oil well pumping units for the purpose of providing an audible and visual warning to people in the area of the pump that the pump is about to start operating. The safety alarm is connected to the existing time-clock in the control system and delays the start-up of the oil well pumping unit for approximately one minute while the audible and visual alarm is activated.
A large majority of the oil well pumping units in the U.S. operate on a time delay basis controlled by a time clock that will start and stop the oil well pumping unit at given time intervals. This intermittent operation increases the amount of oil pumped by allowing the well to recover pressure, but also causes a dangerous safety hazard. When the oil well pumping unit is in a dormant state, often people stand on or around the pumping unit, unaware that the pumping unit will restart at any moment, resulting in people being injured and even killed. Automatic start units have warning signs and sometimes fences in place, but these are not enough. Our invention includes a loud beeper, and if desired a light, on a sixty-second time delay relay which installs easily on the existing oil well pumping unit time clock. Before the oil well pumping unit can begin pumping, a loud one-minute warning signal is given, alerting workers and other people that the oil well pumping unit is about to begin pumping.
2. Description of Related Prior Art
Audible and visual alarms warning of a pending start of machinery are well known. U.S. Pat. No. 1,709,517 issued to Arthur E. Billingsley on Apr. 16, 1929 discloses control of both warning lights and normal lighting activated by a manual start-button to warn people of a pending start of machinery such as a printing press. Similarly, U.S. Pat. No. 1,790,681 issued to Hugh L. Smith on Feb. 3, 1931 discloses the use of a flasher relay to flash lights as a warning of pending operation of machinery such a printing press. Again, the alarm system is activated by operation of a manual start-button to initiate manual operation of the machinery. U.S. Pat. No. 4,266,221 issued May 5, 1981 to J.C. Hawkins discloses an alarm circuit which is interlocked with the start circuit of power-driven industrial machinery so that before the machinery can be started an alarm must be energized for a predetermined time to alert people that the machine is about to start. According to the Hawkins disclosure, in the event that the machinery is not started within a predetermined time after termination of the alarm, or in the event that the alarm has not actually sounded, the whole cycle must be repeated. U.S. Pat. No. 4,821,024 issued to Allan T. Bayha on Apr. 11, 1989 discloses an advance warning system for an automatic electric door operator in which a command signal originating from a remotely located hand-held radio transmitter or a wall switch located within the garage is received and processed by a signal receiver and transmitted to a signal delay unit. Upon receipt of the command signal, the delay unit activates a warning light and warning horn to alert people in the vicinity of the door or operator mechanism that the operator is about to be activated. After a predetermined delay period, the delay unit also generates an operating signal which activates the operator.